Abstract:

Two novel routes (radiation and foaming) are presented in this research to recycle and utilize the waste rubber powder such as ethylene propylene diene monomer (W-EPDM) for making high-end composites using low density polyethylene (LDPE) as a matrix as it indicated better results over polypropylene (PP) matrix. Highly effective, eco-friendly ultrasonic, as well as microwave radiation and supercritical foaming methods are used to making respective composites and their subsequent characterizations. W-EPDM was treated separately by optimized microwave and ultrasonic radiation. Effect of compatibilizer such as ethylene octane elastomeric copolymer (POE) on the enhancement of mechanical properties of composites was also studied in addition to the radiation treatment. The enhancement of tensile strength and elongation at break of composite with microwave treated W-EPDM were increased up to 41% and 62%. Corresponding values were found 44% and 68% for ultrasonic treatment. Higher amount of energy during microwave treatment induced larger and localized cavity formation on the surface of composite results reduction of tensile strength as confirmed from surface morphology study. On the other hand encapsulation effect of POE only found to be useful to enhance tensile strength of the composites up to 30% with untreated W-EPDM and LDPE. No significant additional strength increase over microwave and ultrasound treatment was found upon using POE. The encapsulation effect of POE was found disappeared when the radiation was applied. FTIR and DMA study revealed the existence of only physical interaction upon microwave and ultrasound treatment. In this study a composite has also been prepared by mixing waste ethylene-propylene-diene-monomer (W-EPDM) and low density poly ethylene (LDPE) foaming with supercritical carbon dioxide (CO2). In order to optimize the foaming process of W-EPDM-LDPE composite, the variations of pressure, temperature on foamed microcell formation were studied. As indicated in scanning electron microscope (SEM) photographs the most uniform microcellular pattern was found at 200 bar pressure and 100 °C temperature using 30% by weight of W-EPDM. Carbon dioxide (CO2) could not be dissolved uniformly during foaming due to extensive cross-linking of W-EPDM used for the composite. As a results the presence of un-uniform microcells after foaming were observed in the composite matrix to impart inferior mechanical properties to the composite. This problem was solved with uniform foaming by increasing the crosslink density of LDPE using 1.5 phr dicumyl peroxide (DCP) that enhances composite tensile and compressive strength up to 57 % and 15 % respectively. The proposed composites following both treatments have the potential to be used as automobile mats, and foaming mat for artificial turf.

Keywords: Microwave, Ultrasound, Foaming, Composites, Waste-EPDM  

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Biography：

Professor, Polymer Sci. & Eng.

School of Nano and Advanced Materials

Gyeongsang National University

EDUCATION

l   University of Akron, Ohio, U.S.A, PhD in  Polymer Engineering (1989)

l   Yonsei University, Seoul, South Korea, MS in Chemical Engineering (1981)

l   Yonsei University, Seoul, South Korea, BS in Chemical Engineering (1978)

Ph.D. DISSERTATION

Analysis of Flow and Mixing Behavior in an Internal Mixer with Different Rotor Designs

Advisor: James L. White (University of Akron)

ACADEMIC AFFILIATED:

l   President -  Korean Study Group of Elastomer (1996-present)

l   Member -  ACS (American Chemical Society) Rubber Division (1993-present)

l   Editorial Board  -  Korean Institute of Resources Recycling(2000-present)

l   President -  Korean  Rubber  Society (2009-2011)

l   Member -  Korean Rheology Society(1990-present)

l   Director – Korean Polymer Society(1990-present)

CHAIR PROFESSOR :

l  Sandong University, China(2011-2014)

l  Qingdao University of Science & Technology, , China (2001-present)

 ü  Composite materials and structures center - Michigan State University, USA

Key lab of rubber-plastic (QUST),Ministry of Education- P. R. China